<i>E. faecalis</i> infection induced intracellular ROS production.

<p>MKN74 cells infected with <i>E. faecalis</i> for 30 minutes at MOI50. (A) Representative fluorescence microscope image of MKN74 cells stained with ROS detecting probes (green) and superoxide detecting probes (orange) Scale bars = 50 µm. (B) Quantification of fluorescence intensity using the LSM 510 software. A statistically significant increased intracellular production of ROS (p<0.01) and superoxide (p<0.02) in the infected cells compared to uninfected control cells was observed. * denotes significant difference. (C) Fluorescence image showing MKN74 plasma membrane (red) and <i>E. faecalis</i> (green) after 4 hours of infection. Flanking images show the YZ and XZ plane. (D) Split image of C. No evidence for bacterial invasion of the cells was observed.